The MB BS line is getting to me. I paid an independent over $800 to replace the pump and do the filter upgrade, thinking I had to get the filter done to have the right number and correct type of lines. When the fuel gauge had the problem referenced above, I figured it would be easier to fix it myself.
I fixed the gauge and found the pump only has 2 lines. My mechanic said it was "OE" but it doesn't have the Mercedes logo on it. Turns out all the replacement pumps are advertised as OE so my mechanic wasn't lying. However, they only cost $65.20 on-line and are delivered overnight. Thing just pops right in!
Best to just tear into problems and not invent complicated reasons why you shouldn't get started, like always.
Here's the video of a replacement done using only a Leatherman tool:
https://www.youtube.com/watch?v=F89csULKJGY